1. Field of the Invention
The present invention relates generally to a remote access service based on a home network middleware protocol, Universal Plug and Play (UPnP) and more particularly, to a filtering method and apparatus for restricting disclosure of information about one or more physical home network devices during the use of a remote access service.
2. Description of the Related Art
In general, a home network is configured as an Internet Protocol (IP)-based private network. The home network is intended to connect all electronic devices used in a household, such as Personal Computers (PCs), intelligent products, wireless devices, etc. as a network in a common virtual computing environment called middleware and control them.
Middleware enables communication among digital devices by connecting them in a peer-to-peer manner. Middleware proposed so far includes Home Audio and Video Interoperability (HAVI), UPnP, Java Intelligent Network Infrastructure (Jini), Home Wide Web (HWW), etc.
Since modern operating systems support Plug and Play (PnP), installation and setup of PC peripheral devices has been facilitated. UPnP extends Plug and Play to an entire network based on standard Internet technologies such as Transmission Control Protocol/Internet Protocol (TCP/IP), Hypertext Transfer Protocol (HTTP), and Extensible Markup Language (XML), so as to build a network, particularly a home network with various electronic home appliances, network printers, and network devices like Internet gateways.
A UPnP network includes a Controlled Device (CD) that is controlled in connection to an IP-based home network and a Control Point (CP) that controls the CD. In the UPnP network, the CD communicates with the CP in the following stages using the UPnP protocol stack architecture, which includes Internet protocols such as TCP/IP and HTTP, and technologies such as XML and a Simple Object Access Protocol (SOAP).
A first stage is addressing. The CP and the CD are given respective IP addresses. When joining a network, the CD receives its own IP address using the Dynamic Host Configuration Protocol (DHCP), or is assigned an IP address using automatic TCP/IP addressing in the absence of a DHCP server on the network.
The second stage is discovery. The CP discovers the CD or the CD announces its presence. The discovery stage is performed using the Simple Service Discovery Protocol (SSDP). If the CD is added to the network, the CD transmits an SSDP alive message to the network using IP multicast, and the CP receives the SSDP alive message and is thus aware of whether the CD is connected to the network. When a new CP joins a network, the CP multicasts an SSDP Multicast-search (M-search) message to the network. Upon receipt of the SSDP M-search message, CDs transmit M-search response messages including information about the CDs to the CP.
The third stage is description. The CP checks the contents of a description of the CD. The CP checks the response message received from the CD and, if necessary, may request the CD send a more detailed description about itself. In response to the request, the CD transmits its information in the form of an XML document.
The fourth stage is control. The CP operates a CD by controlling its functions. In order for the CP to control the CD, the CP transmits a message selecting the desired service based on the detailed description of the CD to the CD using SOAP. SOAP is a protocol written in XML over HTTP for the purpose of receiving and transmitting Remote Function calls (RFC).
The fifth stage is eventing. The CP learns of an event change of the CD by eventing. When the CP wants to receive an event message from the CD, the CP transmits an event subscription request to the CD. If the subscription is successful, the CD transmits an event message to the CP using the General Event Notification Architecture (GENA).
The sixth stage is presentation. The CP represents the state of the CD using HTML.
The UPnP CD may provide the CP with various services (functions) based on this UPnP basic control method (i.e. the UPnP device architecture). For example, the UPnP CP may control a UPnP CD to copy Audio/Video (A/V) contents stored in the UPnP CD to another UPnP CD according to the UPnP basic control method. If the UPnP CD is a gateway, the UPnP CP may change and set an IP address range, subnet addresses, gateway addresses, etc. for allocation to in-home devices by controlling the UPnP gateway CD. Also, the UPnP CP may provide Remote Access (RA) service that enables remote access to a UPnP home network.
A UPnP RA service device may allow a user to set whether information about a home network device should be disclosed through a manager User Interface (UI) (e.g., a management console, etc.) by providing a filtering method for controlling disclosure or non-disclosure of information about the home network devices.